List the primary international distress frequencies across different radio systems

A. VHF: Ch 16 (156.800 MHz) voice + Ch 70 (156.525 MHz) DSC | MF: 2182 kHz voice + 2187.5 kHz DSC | HF: 4125, 6215, 8291, 12290, 16420 kHz | 406 MHz: EPIRB/PLB satellite | 9 GHz: SART radar

B. All VHF channels below Ch 16 are designated as distress frequencies

C. Only Ch 16 is an international distress frequency — all others are secondary

D. VHF Ch 16 and 406 MHz EPIRB are the only internationally recognised distress means

A. To operate the radar system remotely

B. To broadcast weather forecasts to other vessels

C. To make telephone calls from the vessel to shore

D. To send a digitally coded distress alert containing the vessel's MMSI and position automatically to all DSC-equipped stations and the Coastguard

A. Maritime Mobile Service Identity — a unique 9-digit number identifying the vessel; without it a DSC distress alert cannot identify the vessel to rescuers

B. A GPS waypoint identifier used in coastal navigation

C. A VHF channel number allocated by Ofcom for distress use only

D. A vessel survey certificate number required by the MCA